Telephone system



April 25, 1933.

SUB.

H. W, ULRICH TELEPHONE SYSTEM Filed NOV. 27, 1931 5 Sheets-Sheet l /NVENTOR W. UL RICH A TTORNE Y Filed Nov. 27. 1951 5 Sheets-Sheet 2 /NVENTOR H. W. UL RICH A TTORNE Y April 25, 1933. H. w. ULRICH TELEPHONE SYSTEM Filed Nov. 27, 1951 5 Sheets-Shea?l I5 NL h EU MW. H

A TTORNE Y April 25, 1933. H. w. ULRICH TELEPHONE SYSTEM Filed Nov. 27, 1951 5 Sheets-Sheet 4 A TTORNEV /N VEN TOR H. n. UL R/cH nvm.

April 25, 1933.

H, W. ULRICH TELEPHONE SYSTEEM Filed Nov. 27, 1931 5 Sheets-Sheet 5 /NvENToR H14. ULRICH A TTQB/VEY Patented Apr. 25, 1933 UNITED STATES PATIENT orifice HORACE W. ULRICH, OF NEWARK, NEW JIERSIEIY,` ASSIGNOR'TO BELLA TELEPHONE LABO- RATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION E` NEW YORK TELEPHONE SYSTEM Application filed November 27, 1931. Serial No. 577,571.

This invention relates to telephone systems employing both manual and dial equipment and has for its vobject to increase the efficiency with which connections are established between such oiiices.

More particularly the invention concerns the establishment of connections which originate in dial oiiices and are completed by means of manual operators. In the pastthis type of connection has been accomplished by the aid of a visual indicator located at each operators position. More recently a development has arisen' by means of which the wanted line designation is transmitted to the operator by means of mechanically generated voice currents, rep-` resentative of the elements of the designation. The present invention has to do with the operators equipment for completing connections extended from oiiices providedV with such call announcing equipment.

One operator may serve calls incomingfrom both manual and dial offices and may be equipped with a common control circuit which is automatically associated with the trunks over which calls are incoming. To distinguish between calls incoming from manual offices and those incoming from dial oiiices, the trunks incoming from dial oiiices are equipped with means for identifying themselves to the control equipment and the control equipment is provided with means for transmitting a signal tothe dial oi'lice for causing the initiation ofthe call announcement in response to-such identification. This signal consists of the momentary reversal of the current -flow over the trunk. After the connection is completed the response of the called subscriber causes 40 a prolonged reversal of the current flow for supervisory purposes. If thecalled line is busy, the plug of the trunk is inserted into a busy-back jack which causes repeated reversals of the current flow as a busy signal.

Vhen the calling subscriber in the dial office disconnects, the restoration of the automatic switches renders the trunk selectable and causes the display of a disconnect signal before the operator. If she delays removing l the plug-,tis possible to reselect' the trunk and prepare for'the transmission of a call announcement Vwhile the plug is in the busybaclrjack or in the jack of a 'called subscribers line whose receiver may be off the switchhoolr. To prevent such a p condition from causing premature operation of the call announcer equipment, means is provided responsive to the disconnection of the iirst calling subscriber to restore the direction of current flow to normal and to prevent its reversal until the plug has been withdrawn. Should such release and reseizure occur before the operator-s control equipment is disconnected from the trunk, the control equipment is rendered inoperativeuntil the operator operates her disconnecting means. Release ofthe incoming `end of the connection at this time causes the application of a tone to the operators headset to notify her that the callhas been abandoned. i

The invention will be more clearly understood from a consideration of thefollowing description in connection with-the drawings in which: i

Fig. l shows in diagrammatic form a connection lbetween a manual substationand the trunk of Fig. 8.' f Fig. 2 shows in diagrammatic form a con-- nection between a dial substation and the trunk of Fig. 4.

Fig. 3, shows ka trunk incoming from a manual oirice.

, Fig. 4 shows a trunk incoming from a dial oiiice. t v

Fig. 5 shows the operators telephone and controlequipment. l f 1 Fig. '6 shows the common ringingy key equipment; and

Fig. `7 shows the manner in which the several figures should be arranged.

For a detailed description of the call announcing'system as used in connection with a tandem sender, reference is made to the patent of T. H. Roberts, No. 1,840,132, granted J an. A5, 1932. y

lVhen the subscriber at substation 100 wishes to talk with the subscriber at substay tion 332, he removes the receiver from the switchhook lighting a lamp (not shown) bef the answering plug of her cord circuit 101 in the answering ack of the subscribers line- He then gives the number of substation 332 to the operator who inserts the calling plug of the cord circuit 101 in the jack 102 connected with the trunk of Fig. The insertion of the plug in jack 102 closes a circuit from ground over the sleeves of the jack and plug for lighting supervisory lamp 103. Attlie saine time acircu-it is closed from bat-- tery through the lower right winding ofthe cord circuit repeating coil 105, supervisory relay 104, rings of the plug, ack andl trunk, lower left winding of repeating coil 3.00,. windings of relay 301V in series, upper lett vinding of repeating coil 300, tips odi trui-ik, jack andA plug, upper right winding; ot repeating-*coil 105 to ground. vRelay 301 op.- erates in-v this circuit, but relay 104 can not operate due to the high resistance of the right wind-ing of relay 301. Relay 301 causes relays- 302 and 303 to operate in turn.. Re lay 303 closes a circuit irombattery through guard lamp 313, resistance 312, inner lower back contacts of relays 3,11 and 310: to ground at the inner left contact of relay 303 as an indication that a call is incoming overA the associated trunk. Relay 303v also. connects ground over itsV outer left contact, back contact of relay 333, outer lower back contact of relay 314, inner left back contact of relay 315 to conductor 3.04` and over the outerlower back contact or relay 31:0 to conV ductor '305.

Conductor 305` extenzdsto the winding' or relay 406 which is connected over conductor 408 to the right contact oli relay andi bat-- tery. Relays 406`and' 407 comprise'a pai-ref sequence relays individual to the trunlr of Fig, 3, while the relays 416- and 417 are a similar pair of'relays-individual to the tru-iik of Fig. 4 and other pairs of relays,-provid ed for-the remaining' trunks at the-operators position, are indicated by thedotted sections of the conductors associating the' two pairs of sequence relays. The function of these relays is to connect the operators con'- trol circuit of Fig. 5 andthe commonl ringing key circuit of Fig. 6 with the trunk cir'- cuit in a predetermined sequence, regardless of the order in which the trunks are selected. A trunk splitting circuit would ordinarily be provided by means of which one operator can serve groups of trunks of varying size, but it has been omitted from the disclosure. A typical' splitting arrangement is disclosed in Patent 1,667,830granted to W. Ulricli, May l', 1928; Y

Assuming that the call on the tiuiik of Fig. 3 is the only one present at the `time,.re lay 406 operates in the circuit above traced and closes a circuit from battery through the winding of relay 407, outer front Contact off relay 406, over the back contacts of similar' relays belonging te intermediate trunks:

over the back contact of relay 416, conductor 418, winding of relay 502, back contact of relay 503 to ground. Relay 407 in opera-ting disconnects battery on conductor 408, from other relays similar to relays 406 and 416 of trunksl higher in the chain, while relay 406 opens*v the operating ground for relays such as relay 407 which may be lower in the chain.

When the opera-tor occupies hei' position, she connects lier headset including receiver 507 and transmitter 508, with the position equipment by means of a plug and jack (not shown)- A circuit is thereby closed from battery through the winding of relay 509, transmitter 508,. winding o-'l repeating coil 5 34 to ground. Relay 509, operating in this circuit, operates relay 510, in turn operating relays 511 and 512. lith these relays op erated the position is ready to handle calls. 1llhi-letheposition is unoccupied, relay 504 is operated over a back con-tact oi relay 510 and a circuit is closed for giving an indica-- tion that a; call' has been: received on an u-nattended position;

-Wi'th relays 510, 5111 and-l 512 operated, the opera-tion oi relay 407 closes a circuit from, battery over the iii-iddle right contact of relay 407, conductor 423,. inner lower contact of relay 512,k conductor 513, winding et relay` 6061-tol grou-ndi at the' back contact of relay 608.- Relay 606-coiinects-battery thi-'oughiiliterruptei 607 to-conductor 422,. inner right Contact ot. relay 407, conductor 339,. to resista-nce 3112,. shunt ot lamp 3.1-3- so that lamp, 3];3 is ,intermittently extinguished. Inadrlitioin relays 4061 and 407 close a circuit from battery over the rigl'it front contact of relay 303,. outer left backcontact of relay 315', upper winding of relay 319-, conductor 309, outer leiit Contact of' relayy 407,. inner right Contact of relay 406, conductorl 420, outerl left contact of: relay 5111,. conductor 505,-. resistance 601,. loa-ck Contact of relay 602,. back contact, of relay 603 to ground. Relay 319:l locks over its inner upper contact', conductor 321, middle lower contact of relay. 510,. conductor 506, winding of relay 604s, back contact of'relay605 to ground. Relay.- 319fcennects the` operators control circui-t toi thetrunk thereby preparing for the transmission ofV the wanted: number to the opera-tor and the control of` the ringing equipment by the operator.

Relayi 604 also operates in this circuit closing an obvious circuit for relay 603 which:

locks over its inner left contact, conductor 538, middle lower contactof relay 512', outer right backv contact' off relay V514, winding of relay 5115 to4 ground. Relay 515 starts the transmission ofthe order tones toV the originating operator`- and to' the B operator. To do soit closes a circuit from the tone source through the primary windings otk toney coils 521* and back Contact of relay. 5,18

to ground at the inner right Jfront contact of relay 515. At the same time it connects the secondary of tone coil 521 over its inner left contact, through condenser 536, outer lower back contact of relay 519 to one of the windings of coil 533 for transmitting the tone to the B operator, and connect-s the secondary of tone coil 517 to the trunk over a circuit extending from the tip conductor, outer upper contact of relay 319, conductor 324, upper contact of relay510, upper back contact of relay 519, secondary winding of tone coil 517, outer right contact of relay 515, inner lower back contact ot' relay 519, condenser 520, inner lower front contact oi' relay 510, conductor 345, outer lower front contact oit' relay 319, to the ring conductor thereby transmitting a tone to the originating operator. In addition relay 515 closes an obvious circuit for relay 518. Relay 518 in operating opens the primary circuit of the tone coil andy extends its own operatingV ground to the winding ofrelay 547. Relay 547 recloses the primary circuitnot' the tone coils over its right contact to ground at the lower normal Contact of relay 531 and in turn operates relay 531. Relay 531 opens the primary circuit of the tone coil thus terminating the second impulse of tone. lt also closes a circuit from battery through the winding of relay 519, upper contact of relay 531,inner right back contact of relay 514, inner upper back contact of relay 530, to ground at the outer right contact of relay 524. Relay 519 disconnects the secondary winding of coil 517 from the tip and ring conductors of the trunk and connects the secondary winding of repeating coil 534 to the trunk. It also vdisconnects the secondary of tone coil 521 from repeating coil The termination of the second impulse of tone informs the originating operator that the B operators telephone has been connectedV to the trunk and she then transmits the number ot the wanted subscriber. The B operator thereupon tests the wanted lline by touching the tip of plug 330 to the sleeve of jack 331. Yfrom the associated trunk is transmitted over the sleeve of jack 331, tip of plug 330, upper normal contact of relay 310, conductor 340, inner upper contact of relay 512, through the winding of test repeating coil 533 to ground, producing a click in the operators receiver. Y

Then relay 603 operated as above described, it removed the operating ground trom relay 319 causing that relay to be held under the control of its locking circuit only. Relay 603 also closes an obvious circuit for relay 610 which in turn operates relay 602 and relay 613. In' addition relay 603 closes a circuit from battery through the winding of relay 612, back contact of relay 611.V to

It the line is busy, battery Having found the wanted line idle, the

operator then operates one of the common ringing keys 620 to 623. These keys when operated operate the corresponding relays 630 to 633 and connect ground to conductors 342 and 343 to select the properringing current tor signaling the wanted subscriber. Key 620 connects ground to both conductors 342 and 343; key 621 grounds conductor 342; key 622 grounds conductor 343; key 623 grounds neither conductor. All four keys operate relay 625 which grounds lconductor 344. In the trunk circuit ground on con` ductor 342 operates relay 314; ground on conductor 343 operates relay 326; and ground on conductor 344 operates relay 315. Relay 314 determines whether ringing current is` applied to the tip or the ring conductor, while relay 326 determines whether source 336 or 338 shall be used and relay 315 starts the ringing. y

` Assuming that key 620 is operated, a circuit is closed from ground through the winding of relay 618, conductor 543, inner right contact of relay v511, conductor 542, vconductor 344, middle lower contact of relay 319, right winding of relay 315, outer lower back contact of relay 311 to battery. Relay 618 Operates, but relay 315 vwhich is marginal can not operate in series with relay 618. Relay 618 connects battery through the windings of relays 617 and 630 in series to key 620. Relay 617 operates, locking to kbattery over its inner front contact. Relay 630 also operates, connecting ground from key 620 through resistance 619 vto conductor 342, over its outer left contact ance 619 to conductor 342operates relay 314 which locks over its outer lower contact to thesame circuit as relay 326. Relay 615 is also operated in a. circuit over conductor 546, outer right contact of relay 511, conductor 545, right contacts of relay `630 to ground at key 620. Relay 615 locks over its left contact to relay `612 and opens the locking circuit of relays 612 and 611, which release, in turn releasing relay 615 as soon as the ringing key is opened' Relayv 615 provides a holding circuit -for relay 610 until the key is released. In addition it eX- tends its holding ground back over conducter 546 and the front contact of relay 511 to conductor 545 and the right contact of relay 630 to hold that relay operated until after relays 612v and 615 have released in case the closure of the ringing key is very short. Since relay 625 is slow to operate, ample time is provided for relays 314 and 326'to operate before the operation ot' relay 315.

Relay 315, in operating, locks in a circuit trom battery over the right contact of relay 303, middle lett iront contact and lett winding ot' relay315, back contact ot relay 333, outer `left contact of relay 303 to ground. Relay 315 disconnects ground from conduc` tors 304 and 305 releasing relay 406 and in turn relay 407. The release otthese relays opens the intermittent shunt around lamp 313 permitting itv to ,again light steadily. Relay 315 also opens the lockingv circuit ot relay 319, thus completing the disconnection of the trunk from the operators'control circuit. The operator now inserts plug 330 in jack 331, operating-f relay 310 over the. sleeves of the plug and jack. The operation of relay 310 opens the circuit of lamp` 313 eX.- tinguishing it. Vith relays. 310 and 315 operated,l a circuit is closed for ringing re lay 327 :trom ground over the inner upper contact of relay 310, right contact of relay 315,v winding and inner upper normal contact ofi relay 327, outer upperl front contact of relay 314, pick-up. interrupter 334 to battery. Relay 327 operates in this circuit and locks over its inner upper front contact togbattery at the right front contact of relay. 303. Relay 327 completes the ringing circuit prepared by relays 314, 326 and. 315; This circuit may be traced from ringing source 336 through interrupter 335, outer lower front contact ofrelay 326, .winding of relay 333, innerV lower front contact of relay 314, upper front contact ot relay 327, upper back contact of relay 311, outer upper front contact of relay 310, tips of plug`330 andjack 331, over the subscribers line and ringer, over the rings of jack 331 and plug 330, middle lower back Contact of relay 311, lower front contact of relay 327, inner upper iront contact ot relay 314 to ground. The subscriberV is signaled over the circuit above traced, while ringing tone is transmitted back to the calling subscriber through condensers 329 and 328. llVhen the called subscriber answers, relay 333, which was included in the ringing circuit, operates openingV the locking circuit of relays 314, 315, and

326. The release of relay 315 opensthecircuit of relay 327 which restoresthe talking conductors andpermits conversation to take place. When thc talking circuit is completed, relay 325operates in series with the v-subscribe1"s line, closing a shunt around the relay 303 releases, a circuit is closed from battery over the right back, contact` ot' relay 303, winding of relay 311 to. ground at the inner upper front contactoi relay 310. Relay 311 locksto battery over its lowermost contact and connects ground over its inner lower contact to resistance 312 and lamp313 lighting the lamp as a disconnect signal. Relay 311 alsov opens the tip and ring conductors. VlVhenrthe plug` is withdrawn from the jack, relay 3.10 releases in turn releasing relay 311 and extinguishing lampA 313.

It the trunk should' be reselected at' the originating oliice while. plug 330 is still in jack 331.v` that is, with relays 310 and 311 operated, the operation of relays 301, 302 and 303. connects` groundv to conductor 305 over' the front contacts of: relays 303 and 3,11. Relays 406,. 407 and 319 operate and the circuit functions as described hereinbefore. After the order is received from the originating operator,.plug 330 must be rcmoved. from jack 331 before the ringing relays can be operated and the trunk disconnectedl from the operators control circuit, since'with relay 311 operated, battery is disconnected. from, the loperating winding of rela 315.A

T is* operators position is alsol equipped, as stated. previously, to handle callsincoming from panel o Aces at which the call is registered and. transmitted. to' the manual oiiiee by meansA of'automatically generated voice currents, transmittedy by a call announcer machine.V A trunk. incoming. from such an oii'ce is shown in Fig. 4. i

Assume. that the subscriber at substation 150 ina dial ofce wishes to converse with the subscriber at substation 432, hewillbe connected by means of, line finder 151 with the sender 152 which will record the wanted number to control the selection ot the trunk outgoing to the desiredl manual office by district selector 154and otti'ce selector 155. The call announcer' machine 153` will.y then be con.-

nected with the sender and prepared for op-i eration. When the sender is ready for the transmission of the call announcement, it bridges arelay across the trunk conductors, completing a circuit through the left windings of repeating coil 400, back contacts of relay 452 and the windings of relay 401 to battery and ground. Relay 401 operates closing an obvious circuit for relay 403`which lights lamp 413 and operates relay 416 if no trunk lower in the sequence has been seized at the same time. Relay 416 in turn operates relay 417. The operation of relays 416 and 417 causes the connection of the operators control circuit with the trunk in the manner described for relays 406 and 407. However, this trunk differs from the trunk of Fig. 3, in that it is provided with a relay 454 which identifies the trunk as one incoming from an oiiice equipped with a call announcer machine. Therefore, when relay 419 operates to complete the connection of the control circuit with the trunk, a circuit is closed from battery at the right front contact of relay 403, winding and normal contact of relay 454, outer upper front contact of relay 419, conductor 324, upper front contact of relay 510, outer upper back contact of relay 530, winding of relay 522 to ground. Marginal relay 454 does not operate in this circuit, but relay 522 does, in turn operating relay 523 which in turn operates -relay 524. Relay 524 connects ground through low resistance 525 in shunt of the winding of relay 522 and connects ground through resistance 526 to the lower back contact of relay 530, lower back contact of relay 532, inner lower front contact of relay 510, conductor 345, outer lower front contact of relay 419, winding of relay 425, lower right winding of repeating coil 400 to battery. Relay 425 operates in thiscircuit, in turn operating relays 452 and 453. Relay 452 reverses the connection ofbattery and ground through relay 401 to the incoming end of the trunk, thereby transmitting a signal to the sender at the panel tandem Voffice that the wanted number may be transmitted.

The connection of ground through low resistance 525 in shunt of the winding of relay 522 causes that relay to release in turn releasing relays 523 and 524 thereby opening the circuit of relay 425 and restoring the direction `of current flow over the incoming trunk to terminate the signal to the distant tandem oiiice at the termination of which signal the designation is transmitted. The connection of ground through low resistance 525 in shunt of the winding` of relay 522 also reduces the resistance in'series with relay 454 sufficiently to permit that relay to operate, locking over its upper` front contact to ground. lVith relay 454operated, as soon as relay 453 releases, following the termination of the signal to the sender, the

tip conductor of the trunk isconnected over the back contact of relay 453, lower front contact of relay 454, outer upper contact of relay 419 tov conductor 324and thence to the operators telephone, thus completing the circuit over which the designation is transmitted to the B operator. The callis completed at the manual oflice in the manner above described, the dial equipment functioning in the well known manner to establish the talking circuit atthat oiiice. The operation of relay 425, followingl the responseV of thecalled subscriber, reoperates relays 452 and 453 to` again reverse the direction of current How through the trunk for supervisory purposes. When relay 403 releases at the termination of the connection, relay 454 also releases. l Y y lIn the control circuit the tone relays 515, 518, 547 and 531 operate `as previously described. However, during the time that relay 524 is operated, ground is removed from the operating circuitof relay 519 so that it will not be operated before the signal to the sender is terminated. Otherwise, the operation is. the same as for vstraightforward manual trunks. f

If the B operator inserts the plug ofthe trunk, for example, plug 330 in the jack 331 of the wanted line, before operating one of the common ringing keys, relay 310 operates over the sleeves of the plugand jack. Relays 406 and 407 are held operated vunder this condition in a lcircuit from battery over conductor 408, winding of relay 406, inner left contactof relay 407, conductor 304, innerleft back contact of relay 315, outer lower back contact of relay 314,.back contact of relay 333, outer left Contact of relay 303 to ground. rlhe circuit for steadily lighting lamp 313 extends through resistance 312, inner lower back contactof relay 311, inner lower front contactof relay 310, inner upper front .of relay 319 to ground over the locking circuit of that relay. The circuit for flashing the lamp remains as previously traced. When the ringing key has been operated relay 319 releases, thusvremovingvground from lamp313 and extinguishing it. The operation iof the ringing key operates relays 315, 314 and 326 according to the party to be signaled. RelayA 3 15 opens the circuit of the sequenceV relays and these relays release. 1

I f for any reason the automaticlistening circuits fail to function, the operator can connect her telephone with a trunk'b-y the the same circuit as traced for automatic listening, connecting-the trunk -With the control @c-ir'u-it. Ilovvever, lamp 313 does not flash since thesequence relays have not been operated. In-the-control circuit, relay 614 operates in turn operating relay 616. -Revla-y 604 operates in -the lock-ing circuit of relay 319, in turn operating relay 603 as for automatic' opera-tion.` With relay l-603 opera-ted, a locking circuit is closed -for -relay 6 16 through 'its right Winding and inner right Contact. Relay 616 'connects ground -to the Winding of relay-608 opening the circuit of flashing relay 606. The operation of -relay 603 causes -the transmission of the tones in the usual manner.

WVhfen the emergency listening keyis to be used, either key 529 or548 -mustalso be operated. 'These keys lock when operated. Key 529 4operates relay 501 to remove bat- -tery from the sequence relays to prevent interference -Witli the progress of a call. Key 548 is operated if -the tone circuits are also out of order. In this case a circuit is closed for relay 514 which in turn operates relay 501. Relay 5 14 connects the tip and ring conductors -to-the contacts of `relay 532 and substitutes relay 528 for relay 515 so that relay 5 281s operated from relay 603 following theconnection of the trunk with the control circuit. Relay 528 in turn operates relay -527 which locks to the front contact of relay 603, disconnecting relay 528 therefrom. lVhen relay 528 releases,'a circuit is closed from battery -through the Winding of relay 532, back contact of relay 528, right front Contact of relay 527, inner right contact of relay "514, upper back Contact ofv relay 530, back Contact of relayV 524 to ground. Relay 532 in operating connects the talking conductors through to the operators telephone. Relays 527 and528 introduce a sufficient delay to permit the completion of the signal to the sender Ybefore connecting the operators rtelephone to the trunk. rlhis is further insured Vby the fact xthat ,ground for the circuit of relay 532 is obtained from the back Contact of relay y524. Key 549 and relay 530 permit the 'transfer to an emergency set of relays (not shown) for transmitting the call announcer signal. l I

Relays 502 and 503 `are used for'applying ground -to sequence relays 406 and 40.7, 416 and 417, etc. 'Relay 4502 operates when the circuit of relay 407 or 417 is closed and locks through its own Contact to ground, in turn operati-ng relay 503. Relay 503 Aopens the operating'fy ground for relay `502. By means of a Vmake-before--break Contact of relays 416, etc., relay 5502 is Iheld operated when a ,pair of sequencerelays releases .if a cal-l is Waiting ona trunk ,further along in the sequence.'V When the llast pair -of sequence relays releases, relay y502 also yre- `lease's,-disconneeting ground from conductor 418 and releasing relay-503. After an interval relay 503 reconnects ground tothe Winding of relay '502. This interval permits lthe relays-such as relays 416er relay 406, of trunks over Vwhich calls are incoming to operate,and-the Waiting calls are connected to the -operators control circuit in sequence as before.

`During the nig-ht Ithere may be insufficient calls to 'Warrantthe operator sitting at the "board or she mayhave so many -positionsto handle -that it is -necessary -to patrol the board instead of sitting at one position. ln that case she Will remove her telephone, releasing relays 509, '510,511 and 512. The release of relay -510 permits relay 504 to operate. lVh'en, thereafter, a trunk -is seized Vat the distant end, 4the sequence re- ,lays' function as above described operating Yrelay-606 over the inner rightfront contact of relay 504, causing the trunk lamp to flash as before. Relay 319 Vis operatedl over the outer right front contact lof relay 504 and locks over the inner left front contact ot relay 1504. With relay 504 operated, battery through the Winding of repeating coil '300 and relay 325 vis also connected over conductor 345 and the outer left contact of relay 504 -to-the night ala-rin, Warning the opera-tor that a call is awaiting her attention. "Neither theorder tones nor fthe order signal can be transmitted. However', as soon as the operators telephone 'is connected with the position control circuit, these circuitsl pan function andthe callprogresses as be ore. If a call is abandoned at the originating end prior to the insertion of the plug in the jack, the release of relay 301 releases relays '.302 and 303, in turn releasing relay 3'19 and any other relays Which may have been operated, restoring the .circuit to normal. lnjthe ringing key circuit it Will 'be remembered that the operation of relay 603 following the connection of the `trunk with the position, operates relay 76112 which locks through the Winding ofv relay 611, but relay 611 could not operate, being shunted by the operating circuit of relay 612. If, now, the call is abandoned, the release of relay 319're'leases relay 604 and in turn 4relays 603 and 610, thereby removing the shunt from the Wind-ing of relay 611. Relay 6111 thereupon operates, in .turn operating relay 602'. Relay 611 also supplies battery to the Winding of relay 617 yand holds relay 602 operated,-preventing the operation of any other relays such as relay 319 until a ringing 'key or trunk key has been operated. It also connects the secondary of tone coil 626 through lits inner righ-t front cont-act, back Contact ofV relay 613 which is now released, conductor 540, condenser 535, outer lower back contact of relay 519, Winding of test coil .533, thus transmitting an abandoned call tone to the operator. Assuming that the operator now operates the trunk key 624, relays 617 and 634 operate in series. Relay 617 locks to battery at its front contact. Relay 684 operates relay 625, but opens the circuit over which relay 315 in the trunk is operated by the ringing keys. Relay625 also operates relay V609, which in turn operates relay 605 removing ground from relay 604, Which would cause the disconnection of the trunk from the control circuit had it not already been released. Relay 634 also connects ground through resistance 619 to conductor 342 operating relay 314. With relay 314 operated and relay 315 non-operated, ground is removed from the sequence relays and the release of the trunk from the position control circuit is completed. The release of key 624 releases relay 314. Key 624 is also used for releasing the control circuit from the trunk when the call is directed to an intercepting operator., l

Vhat is claimed is: Y

1. In a telephone system, an operators position, trunks incoming to said position from a manual oflice, trunks incoming to said position from a Vdial ofce, means at said dial oflice to automatically announce Wanted line designations, common control equipment at said operators position, an operators telephone associated With said control equipment and normally disconnected therefrom, means in said control equipment for connecting said v telephone with said trunks, means responsive to the seizure of any oneof said trunks for automatically connecting said Vcontrol equipment with said trunk, means to identify said trunks incoming from the dial ofce to said control equipment, means in said control equipment to transmit a tone signal to said operators telephone, means responsive to saidl identifying means to transmit a signal to initiate the operation of said announcing means, means normally responsive to the completion of said tone `signal to Vconnect said telephone with said trunk, and means responsive to said identifying means to delay 'the connection of said telephone With said trunk until the termination of said signal.

2. In a telephone system, a dial office, an operators position, trunks connecting said dial ofce and said operators position and terminating in plugs at said position, jacks at said position, a call announcer mechanism at said dial office, control equipment common to said trunks at said position, means responsive to the seizure of one of said trunks at said dial office to connect said control equipment With said trunk, means responsive to the connection of said control equipment With said trunk to cause a .mo-

mentary reversalof the-current flow over said trunk to initiate the operation of said lcall announcer mechanism, other means to reverse the current lioW over said trunk with the plug of said trunk in a jack, and means to render said other means ineffective if said trunk is released and reseized before said plug is removed from said jack.

3. In atelephone system, a dial oflice, an operators position, trunks connecting said dial ofiice and said operators position and terminating in plugs at said position, jacks at saidposition, a call announcer mechanism at said dial oflice, control equipment common to said trunks at said position, means responsive to the seizure of one of said trunks-at said dial office to connect said control equipment With said trunk, a supervisory relay, means responsive to theoper ation of said supervisoryV relay to cause a reversal of the current flovv over said trunk, means'responsive to the connection of said control equipment With said trunk to momentarily operate'said supervisory relay toinitiate the operation of said call announcer mechanism, other means to reoperate said supervisory relay with the .plug of said trunk in a jack,and means to prevent the reoperation of said supervisory relay if said trunk is released and reseized before said plug is removed `from said jack.

4. In a telephone system, a dial ofiice, an operatorsl position, `trunks connecting said dial office and said operators position and .terminating in plugsat 'said position, jacks at said position, a call announcer 4mechanism at said dial office, control equipment common to said trunks at said position, means vresponsive to theV seizure of one of said trunks at said dial oiiice to connect said control equipment With said trunks, a supervisory relay, means responsive to the operation of said supervisory relay to cause a reversal of the current flovv over said trunk, means responsive to the connectionof said control equipment with said trunk to momentarily operate said supervisory relay to initiate the operation of said call announcer mechanism, other. means to reoperate said supervisory relay With the plug oi said trunk in a jack, and means to .disconnect .said supervisory relay fromY said plug to prevent the reoperation of said supervisory relay if said trunk is released and reseized before said plug is removed from said jack.

5. In a telephonesystem, a dial office, an operators position, Vtrunks connecting said dial office and said operators position and terminating in plugs at said position, jacks at said position, acall announcer :mechanism at said .dial office, control equipment common to said trunks -.at said position, means responsive-to the. seizure of'one of' vsaid trunks at said dial ofiice toconnect said control vequipment, With said trunk, asupervisory relay, means responsive to the operation of said supervisory relay to cause -a reversal of the current -floW-ov-er-said `trunk, means responsive to the connection of said control equipment with said trunk to vmomentarily operate said supervisory relay to initiate the operation-'of said-call announcer mechanism, other means to reoperate said supervisory relay 1with the .plug of said trunk in a jack, a relay, means responsive to fthe releaseoif said trunk to operate said relay, and means -under-the control o-said relay to -prevent -the -reope-ration of said supervisory `relay if said trunk is reseized before said plug is removed from-said jack.

6. In a telephone system, an operators position, trunks-appearing at said position, an operators telephone and Vcontrol vequipment common tosaid trunks, means `responsivefto the seizure of one of saidtrunks to automatically associate said control Vequipment VWith said trunk, ringing keys in `said control equipment, means "responsive fto -the operation of one of-said'keys Vfor disconnecting said control equipment .'fromsaidftrunk, and means to rendersaid associationfineiiective if said trunk is released and freseized prior to the operation of one of said-keys.

7. YIn a telephone-system, an-operatorsposi'tion,trunks appearing at-said position, an operators telephone and control equipment common to said trunks, means :responsive to the seizure of one o-'said trunks Yto .automatica-lly associate said control equipment with said trunk, ringing f-keys in-said con-- trol equipment, means responsive -t'o vtheoperation of one of said keys 'or disconnecting said control equipment from said trunk, means responsive tothe releasel of said:trunk prior to the operation of one Vof said keys to disconnect said 4trunk from said control equipment, and means to prevent `the reassociation of said trunk with said control equipment if said trunk is-reseized prior to the operation of one of sald keys.

`8. In a telephone system, -ian operators position, trunks appearing at vsaid position, an operators ytelephone and control yequipment common to said trunks,arelay responsive to the seizure of one of saidft-runks to 'automatically associate said control 4equipment yWith said trunk, ringingkeys in said control equipment, means responsiveto the operation of one ofsaid-keys for disconnecting said control equipment from-said trunk,

Vmeansfto deenergize saidrelay-responsive to therelease of said-trunkpriorto the operation of one of said keys -to disconnect said position, trunks appearing at said position,

an operators telephone and -control equipment common to-said trunks, means responsive to theseizure of one of said trunks to automaticallyassociate said control equipment with said trunk, ringing keys in said control equipment, means lresponsive tothe Aoperation of one ofsaid keys for ydisconnecting said Vcontrol equipment from said trunk, means-to apply a tone to said operators telephone-if saidftrunk is released prior to the operation of one of said keys, and means responsive to the operationof one of said keys to remove said tone.

ll.' In a telephone system, an operators position, trunks appearing at said position, an operators telephone and control equipment commonto said trunks, means responsive to the seizure of one of said trunks to automatically associate said control equipment with said trunk, ringing keys in said control equipment, means responsive to the operationof oneotI said keys for disconnecting said control equipment `from said trunk, means responsivefto the-release of saidtrunk priorto'the loperation of one of said keys to disconnect said Ltrunk from said control equipment, means V'also responsive to such disconnection of said trunk circuit to apply a tone to'said operators telephone, means to prevent vthe reassociation oit said trunk With Vsaid control equipment if said trunk is reseized prior to the operation of one oilsaid keys, and lmeans'responsive to -the operation of one of said keys to-remove said tone andtopermit the reassociation of said trunk -With said control equipment.

. In witness whereof, I hereunto subscribe my name this 23d day of-November 1931. HORACE VV. ULRICH. 

